In the fabrication of many electrical products, it is frequently necessary to establish a plurality of upstanding terminals on a substrate. For example, on printed circuit boards, it is necessary to establish terminal pins to which external wiring can be secured.
In U.S. Pat. No. 3,975,811, issued Aug. 24, 1976, and assigned to the assignee of the present invention, there is disclosed an apparatus for inserting terminal pins into a workpiece, such as a printed circuit board, which apparatus operates on a continuous supply strip of integrally connected terminal pins. In accordance with the invention disclosed in the aforementioned patent, the leading one of the terminal pins on the supply strip is grasped and, thereafer, moved forward past a shearing edge so that the lead pin is severed from the remainder of the supply strip at a point approximately halfway between the adjacent terminal pins. Thereafter, the severed terminal pin is driven into the workpiece.
Although the apparatus disclosed in the aforementioned U.S. Pat. No. 3,975,811 has enjoyed a certain degree of commercial success, there is one drawback associated therewith which the instant invention effectively eliminates. Specifically, with the apparatus of the aforementioned 3,975,811 patent, where a single shear operation takes place by passing the lead terminal past a shearing edge, the web joining adjacent terminal pins is effectively split down the middle, leaving each terminal pin with an undesirable shoulder or abutment protruding from opposite sides of the terminal pin proper. The enlarged central portion of the terminal pin created by these shoulder portions creates accuracy and tolerance problems vis-a-vis the apertures in the workpiece which have been preestablished and manufactured at a different location, and normally by a different manufacturer who may not be aware of the increased diameter of the central portion of the terminal pin occasioned by the aforementioned shoulder regions.